India captain MS Dhoni rued his execution after his team suffered a thrilling one-run loss to West Indies in their first Twenty20.
A 49-ball century from Evin Lewis set up the Windies' 245-6 in the United States, and they just held on to defend it.
KL Rahul made an unbeaten 110 for India, who needed eight off the final over bowled by Dwayne Bravo (2-37).
But they fell short as Dhoni was dismissed off the final ball, leaving the skipper to lament his failure to see his team to victory.
"It was an amazing game. We couldn't have expected more from the batting unit," he said.
"The last ball, the thinking was right but the execution was wrong. Everything is judged by execution."
For the Windies, Johnson Charles made a crucial 79 off 33 balls in Lauderhill, while Rohit Sharma (62) and Dhoni (43) contributed well for India.
Windies captain Carlos Brathwaite said he backed Bravo in the dying overs, but had his concerns.
"When Bravo said he was bowling a slower ball at the end, I told him that he had my backing. But in my mind I was thinking 'really?'," he said.
"We never do things easy, but we held our nerve."
Game two of the series is on Sunday.